Microscopy techniques are used to diagnosis several diseases, hematology conditions, etc. Some microscopy techniques require specialized microscopes or other equipment to achieve sufficient resolution for proper diagnoses.
Microscopes can be used to detect analytes such as malaria using a smear, such as a thick blood smear. Typically, the microscope includes an oil immersion lens having a relatively shallow depth of field to achieve resolutions required to detect the parasitic protozoans that cause malaria. The lens typically exhibits a depth of field that is only a few micrometers, about a micrometer, or less than a micrometer. Typically, an entire thickness of a smear is imaged to conclusively diagnose a condition indicated by the presence of the analyte. However, the thickness of the smear is greater than a few micrometers, which can cause problems with diagnosis, depending on the focal plane of the image. To ensure that the entire smear is analyzed, the distance between the sample and the lens can be decreased or increased to capture multiple focal planes of each field-of-view (FoV) in a smear.
A typical microscope includes a conventional focusing system configured to increase or decrease a distance between the lens and the sample in micrometer displacements. However, such a conventional focusing system can be expensive and complex, which makes the conventional focusing systems unsuitable for areas where is malaria is most prevalent, such as in poverty-stricken areas. Typical diagnostic measures include employing a human technician to scan the slide in the microscope to visually determine if the analyte is present. However, factors that limit the sensitivity and consistency of human microscopists include inter- and intra-person variability, inattentiveness, eyestrain, fatigue, and lack of training. Lack of training is especially relevant in low-resource settings, where highly-qualified microscopists can be in short supply compared to the burden of diseases such as malaria. Additionally, human technicians may not be able to identify or quantify particularly low concentrations of an analyte (e.g., low parasitemia) in a sample slide.
Therefore, developers and users of microscopes continue to seek improvements to microscopes and diagnostic techniques for use in determining a presence of analytes.